Water-softening filter and process of regenerating and purifying the same



y 2, .1929. c. HUFSCHMIDT 1.719.548

WATER SOFTENING FILTERAND PROCESS OF REGENERATING AND PURIFYING THE 5! Filed July 2'7, 192'? /0 ven tor.-

Patented July 2, 1929.

CARLHUISCH HIDT, OI WESTENFELD, NEAR WATTENSC HEID, GERMANY.

warnn-sorrmme FILTER am) raocnss or usnnmrms'mn'ruamme rim Application filed July 2'7, 192?, Serial in. 208,818,

The invention relates to water-softening filters of the kind in which the filtering material effects an interchange of chemical bases, as of sodium and calcium in permu- 6 tite filters. For regenerating and purifying such filters the common method is to fill the same with liquid, sa a solution of common salt, and leave the liquid therein for some hours, whereupon it is discharged. A some- 10 what more elaborate method which has been adopted consists in effecting the regeneration in la ers, from which the solution is drawn 0 separately, but this method re uires very much care. Both these meth s require considerable time, sothat to avoid long interruptions of service an additional installation must be provided, and generally the salt solution used is not capable of being used a ain. To remove these de ects I effect the regeneration and purifying by means of liquid in motion, instead of by liquid at rest, and for this purpose cause the regeneratin liquid to circulate through the filter. fiiis not only greatly accelerates the process, but renders the effect more thorough and uniform. I may, at the beginning of the process, discharge a small quantity of the regenerating liquid, to carry away the dirt which ithas washed out of the filter, and I am then able to re-use the remaining liquid; For introducing the regenerating liquid into the filtering column I prefer to use perforated pipes arranged in tiers within the column, so that the resistance to the flow of liquid is much less than ifthe whole of the li uid were introduced at the bottom, and t ere is less disturbance of the filterin material by the circulating liquid, and the atter acts more uniformly on the anules. I may use the same perforated pipes for introducing the crude water into the filtering, column when the filter is in normal operation obtaining in this case reduced resistance to'flow, and reduce disturbance of the filtering material, and being incidentally enabled to use a filtering column of substantially increased hei ht.

For occasional boiling of the lter with a suitable liquid such as dazitol I may pro- Vide a perforated pipe, bedded in a silica layer column, and I may forated pipes aboveat the bottom of the provide a tier of perthe column, for spray- -the solution is solution, car ing the dirtand a also the advanta e of.

or tier of pipes, em-

and in Germany February 5, 1926.

ing the to surface of theliquid, for a purpose whic will be. described hereinafter.

An example of apparatus according to the invention is shown in the accompanying drawing, in which,

Fig. 1 is a sectional elevation thereof, and Fig. 2 is a'partial plan view, in section, Fig. 3 showing in section a detail, to a lar or scale.

ere is a tank a for the salt solution, which is forced by a pump 6- into the per-. mutite filter a, the latter containing-tiers of perforated delivery tubes d, through which propelled into the permutite, washing the mass. As the solution rises in the fi ter it carries the dirt -with it, for discharge through a waste pipe 8' controlled by a three-way cock e.

.When the top so a lame proportion o water-hardening compoun s, has been discharged, the cock e is turned to cut'oif the discharge through the pipe .9, and the solution then flows back to the tank a whence it is pumped back tothe filter, and

ke t in circu ation as required.

ith this method the (process of regenerating is much accelerate being, in a typical case, completed in half. an hour, whereas formerly nine hours were required. Then the pump is stopped, and a valve is opened, allowing the solution in the ter to flow back to the tank a. The slime and articles of water-hardeners having been discharged at the beginning, the remaining salt solution can be re-used.

The crude water is su zpllied to thefilter at appro riate pressure controlle -by,a valve 9'. A valve z in the delivery p'pe of the pump 6, which joins the pi e h, 'is at this stage closed. Thqipipe it delivers the crude water into the. tering mass through the tubes (1.

Foroccasional boiling of the filter there is a steam pipe controlled by a valve m and leading to a bank of perforated tubes Z close to the bottom of the filtering column. Be-.

granules and loosenin the.

layer of rough a pipe In" fore steam is introduced the filter may be 5 dirt or slime, and

It is a common experience, with permutite filters, that some of the permutite is lost during the process of regeneration, owing to some of the permutite frothing up with the being discharged with the same. To prevent or reducesuch loss I provide at the top of the filtering column a tier of perforated tubes n, located above the outlet to the pipe s and connected to the pipe h by a pipe controlled by a valve 0. Tie connecting pipe joins the pipe it between the filter and the valve 5 so that if the valve 0 is opened while the pump 7) is working solution is sprayed on to the froth or scum and 5 washes out the particles of permutite. As

an additional safeguard I provide at the outlet a froth trap 17, best shown in Fig. 3, with a filter 1" adapted to retain permutite, the froth trap having an overhanging cover, which obstructs the entrance of froth and compels liquid from the top of the column to take first a downward and then an upward course, in order to reach the outlet, as indicated by arrows in Fig. 3.

\Vhat I claim as my invention and desire to secure by Letters Patent of the United States is 1. A water softening filter, comprising a container for filtering material, tiers of pertorated tubes in said container, a tank for solution, a water supply pipe connected to said perforated tubes and having a cut-off valve, a pipe connecting the container with the tank and provided with a cut-off valve, a pipe connecting the container at an elevated point with the tank and having a waste pipe,a three-way valve between said connecting pipe and said waste pipe, peri rated pipes in the upper and lower por-- tions of the container and having a valved connecting pipe, a valved steam pipe connected to said connecting pipe, a pump, a valved pipe connecting the delivery side of said pump to said water supply pipe and a pipe connecting the suction side of said pump to said tank.

2; A water softening filter, comprising a container for filtering material, tiers of perforated tubes in said container, a tank for solution, an outlet pipe eonnecting the container at an elevated point to the tank, a waste pipe leading from said outlet pipe, a. three-way valve to control said pipes, a pump, a water supply pipe to said perforated tubes in the container, at valved pipe connecting the delivery side of the pump to said water supply pipe, a pipe connecting the tank with the suction side of said pump,

)eri'orated tubes in the container means tor Y connecting said first mentioned tubes to the delivery side of the pump, and a froth trap, including a filter, including the intake end of'said outlet pipe. a

In witness whereof I have signed this specification.

' CARL HUFSCHMIDT. 

